ZOOMFACTOR (System Variable)

Controls how much the magnification changes when the mouse wheel moves forward or backward.

Saved in:Registry
Initial value:60

Accepts an integer between 3 and 100 as a valid value. The higher the number, the more the change.

Note: In contrast to versions prior to AutoCAD 2013-based products, the result of zooming in and out by the same number of mouse wheel notches results in no net change to the magnification.